GEOLOGIC RECONNAISSANCE OF MINDANAO AND SULU. 483 



poured out over the surface. This schist is identical with that found in 

 the gorge of the Tumaga Eiver. 



I had observed terraces along the shore farther to the north in the 

 neighborhood of Dapitan and therefore looked for some signs of elevation 

 here. I did find one fairly vrell preserved terrace a few miles to the north 

 of San Eamon, but the streams have cut through it in so many places 

 that only an especially trained eye can see it. This terrace is perhaps 6 

 meters above the mean tide level. (Plate YII.) The mountains in the 

 Zamboanga Peninsula were once covered with a mantle of limestone, but 

 little of the latter remains, a few large bowlders in the streams being all 

 that we could find. 



This coastal strip on which San Eamon is located, disappears to the 

 north at Patalun Point, but it widens regularly to the south and is every- 

 where taken up with coconut culture. The long stretch of sandy littoral 

 from San Eamon to Zamboanga is especially adapted to the culture of 

 the coconut palm. 



This peninsula in regard to its population might be divided into the 

 following zones: 



1. The hill or forestal zone occupied by Subanuns, a wild and primitive people. 



2. The intermediate or rice zone by Filipinos, mostly Visayans. 



3. The coastal plain by Chinese and Americans. 



4. The beach zone by the Moros ( littoral zone ) . 



COAI, MINES AT SIBUGUEY. 



Following the reconnaissances outlined above I went to Sibuguey Bay, 

 an all-night run by Constabulary vessel to the northeast of Zamboanga. 

 I was accompanied on this trip by Colonel W. C. Taylor, then in com- 

 mand of the Fifth Constabulary District. We anchored about a half mile 

 offshore as we did not know the exact configuration of the reefs, this coast 

 being but incompletely charted. 



Our road to the coal measures at Sibuguey was first by boat up the 

 Siay Eiver, the banks of which for some distance from the mouth are 

 lined with mangrove swamps, we taking a turn through an opening in 

 the right bank and following an estuary until noon, when we landed and 

 followed a trail over a low hill to the house of the datu of this region, 

 Lukas, a Subanun. (See Plate VIII.) 



We left this place early in the afternoon and after a very trying march 

 through mud and over hills, we reached the site of the coal workings on 

 the Sibuguey Eiver. The old, abandoned tunnels of the coal mines are . 

 hidden by the underbrush. I could obtain but little idea of the condition 

 of the seams, excepting that they are tilted and dip to the southeast. 

 They can be worked with the mine mouth probably not over 100 meters 

 from the Sibuguey Eiver, which is large enough at this point, 81 kilo- 

 meters from the mouth, to allow small launches and lighters to pass up 

 and dovm to take on coal. 



